2 de Mayo means 2nd of May. The game refers to events that took place on 2 May 1808 in French-occupied Spanish capital Madrid, when local citizens revolted against the French army, the strongest army in Europe at the time. This is a very asymmetric game. It is a short game with simple rules, but it also has a lot of theme. It feels very different playing the two sides of the conflict.
The French are much greater in numbers in this game. To win, they need to kill off all Spanish units, and secure all 4 entry points to the city, by the end of Round 10. The Spanish win if they can prevent this. They can also score an instant win if they kill 4 French units.
At the start of a round, players each draw an event card from their respective decks. These cards can be played any time. You just follow instructions on them. Most are useful to you, but some are a hindrance, or benefit your opponent. There are 11 cards per side, and 10 rounds in a game, which means only 1 card will not be drawn. So knowing the cards well will help you. E.g. there are a pair of Spanish cards which allow a Spanish instant win by killing only 3 French units. Also there is one French card which cancels one Spanish move order in Round 10.
After drawing cards, players secretly write down their move orders for the round. The two side have different rules when moving. The French can only make two orders, except for groups starting in 3 specific areas (main streets of Madrid). Also French units cannot leave an area where fighting is taking place. However, the French can split their groups when moving, unlike the Spanish, whose units must move together once they have met up. The Spanish units can break away from fights though, but they must leave behind half the units to continue the fight (well, I guess more often than not to die holding off the French so that the rest can escape). The Spanish does not have limitations on how many orders they can issue.
Move orders are revealed simultaneously. Then the Spanish move, before the French do. Once movement is done, fighting (where units from both sides coexist in the same area) is resolved. The side with more units kill one unit of the losing side. If you outnumber your opponent by twice the number of units, you kill 2 enemy units. If your numbers are triple that of your opponents, you kill 3, and so on. If both sides are equally matched, noone gets killed.
So the game is very straight-forward: draw card, write and reveal orders, move, fight.
What amazes me is how flavourful the game feels. Michelle (as the French) and I (as the Spanish) played the game without reading any of the cards beforehand (intentionally). The cards add a lot of flavour to the game because they introduce exceptions to the game, making the two sides very different. The movement rules themselves already make the two sides quite different. The game reminds me a little of Lord of the Rings: The Confrontation, because of how asymmetric the two sides are. But of course the gameplay is completely different.
In our game, I started off trying to kill the lone French unit in area 10. The game starts with one French unit in area 10 already engaged in fighting, which means it can't leave, and is a sitting duck because it is surrounded. Unfortunately Michelle played an event card that prevented any French in area 10 from getting killed. What luck. I tried to score an instant win by killing off four French units. At the start of the game most of the French units were outside the city, and those inside were quite scattered. So if I wanted to do this I'd have to do it quickly. Michelle played another event card that effectively sealed off the southern part of the city from me (because she controlled areas 15 and 16 - one of the main streets). Her reinforcements marched into the city slowly but steadily.
I was getting my hand full of useless cards. Holding useless cards is worse than not having cards, because if you hold 3 cards (or more) more than your opponent, your opponent can stop you from drawing cards. There were a few rounds that I couldn't draw cards. I tried to mass my units to fight some of the smaller French groups. I was only able to kill two units before my group was surrounded. It was a lost cause, so my next option was to try to survive until Round 10. I played one event card that allowed my remaining two units to skip one fighting round (i.e. no casualty for that group for that round only). The group was already engaged in fighting. I still held one card that allowed me to add +1 strength. I only had one more round to go. I had planned to move one of my two units out of the fight, to a neighbouring area with two French units. Normally that single unit would have been killed, but with the +1 strength card, I would match the French strength, and would not be eliminated. Unfortunately for me, Michelle had two (!) cards that could cancel my move order. So my plan didn't work out. The last two rebel units were defeated by the French army.
2 de Mayo is quite an interesting and fun game, despite seemingly so simple. After one game, I'm not so sure yet whether the best strategy for the Spanish is to go for the 4-kill instant win, or to try to last until Round 10; to disperse its forces to try to avoid getting caught, or to group together to fight. The game is mostly open information, the only randomness being introduced by the cards. Since 10 out of 11 cards will come into play in every game, the difference from game to game will mostly be in the order the players get the cards. This can affect the players' strategy a lot though. Another factor of unpredictability is, of course, how your opponent makes his move orders. There is some bluffing and double-guessing in this aspect of the game.
Replayability may be a concern, since the main difference from game to game is just the order of the cards appearing. But this may not be a game that you want to play over and over all the time. You probably want to play this 5 - 10 times when you first buy it, and after that only pull it out once in a while.