We recently stumbled upon this game on Steam. It was on sale for just 4.99€ and looked like a lot of fun.
In Bunch of Heroes you play one of four heroes that defend Earth against invading aliens and zombies that look a lot like German WW2 soldiers. But instead of boring you with details let's just have a look at the trailer.
On the Pro side the game is really inexpensive and playing with two people behind the same router caused no issues. The gameplay is easy enough to learn and if you enjoy games like these you'll have a lot of fun slaughtering endless waves of aliens and zombies with all kinds of weapons. There are missions like "Defend this farm", "Rescue the cheerleader" or "Clear this area" that bring some variety into the game.
On the Con side, if you're looking for a deep story, you really should look elsewhere. And even though there are multiple environments to fight in and a whole bunch of different opponents, it's basically all the same. There's also no way to really customize your character or improve stats over time. The only choice you have is what weapons you can pick up during the level.
The repetitive nature of the gameplay can be a major issue if you're playing alone, but playing in a group up to four people can be a blast. Even though you die a lot, characters tend to respawn pretty fast and as long as one character survives, you still have a chance to finish the level.
Conclusion: Bunch of Heroes is a fun game if you have to waste a couple of minutes to hours with a bunch of friends. But if you're looking into a game that can keep you entertained for weeks, you definitely should look elsewhere.