A ridiculously cheap co-op action/tower-defense game!
I had a great time with Zamb!, although I probably don't know how to pronounce that title correctly.
First off, I love it when cooperative games give each player a unique role. Cye has powers that he can use during a level, such as lightning orbs and healing circles, and he predominantly serves as a melee brawler. Chrome, on the other hand, can equip and drop up to three types of towers at a time (the majority of which attack enemies), but only has a ranged weapon.
Outside of each level, towers and powers can be upgraded using the points earned when characters level up. Points can be refunded at any time, so you can re-prioritize if need be. Each level has a few challenges - typically, one of these will involve a certain type of "combo." Combos are activated, I believe, when a few enemies are killed after taking damage from both a turret and a power. Different types of combos result from different combinations of turrets and powers. These challenges and the ability to respec at-will encourage players to experiment. However, I was partial to the cooldown tower (which slows and damages enemies) and the laser sniper (which has good range and penetrates through enemy groups).
Certain aspects of the game (outside of the gameplay itself) have a low-budget feel, but that's hardly surprising with such a low-costed game ($2.99!?). I actually think the developers could safely kick the price up a few more dollars. The game features some odd-looking comic book-style panels between levels, which look like they might've emerged from MS Paint. They aren't awful, but character proportions sometimes appear strange.
The other big issue is with some of the achievements and challenges in-game. After completing all of the 15 levels, my co-op partner and I wanted to go after some challenges and achievements. Unfortunately, there are many issues here. Oddly enough, I acquired the achievement for buying all upgrades for a single power ("I've Got The Power!) although I never played with Cye. In addition, there was a challenge in one level for completion without moving a tower once it is placed. We completed the level once, and although I was sure that I hadn't moved a tower, the challenge was listed as incomplete on the score screen. We played it again and I didn't drop any towers at all (and actually popped the "I'm a Big Boy now!" achievement for completing a level without dropping towers) but still the challenge was listed as incomplete. We decided not to pursue these extra challenges if they were bugged.
Other issues include:
*As you take down enemies, you build up a "boost" bar. You can activate your boost to increase the amount of damage you deal. This boost bar depletes extremely quickly, to the point where it doesn't often feel like it's worth messing with.
*On a few occasions we had difficulty activating our "Zamb!" ability. This ability must be activated by both players at a reactor, and will wipe the screen of enemies. However, if it isn't triggering, you're just standard there hitting X (at least on an XBOX 360 controller) while both you and the reactor take damage.
Although I had a couple issues here and there with meter-based powers and bugs with challenges and achievements, I enjoyed almost every second with Zamb!. If you wanted some replayability, you might even decide to go back through the levels with the other character. A quick tip: levels don't begin until you begin hacking a reactor - therefore, you can usually scrounge up enough resources through destroying red crates to start with a tower on the map.