Darkspore/YMMV

Catharsis Factor: There's an odd satisfaction in destroying large swathes of enemies en masse.
Excuse Plot: All the stuff above? None of it really means anything. Shoot/slash at the enemies in the level to clear it.
- Especially since there are few cutscenes, except with the HELIX computer. And that just directs you towards the next planet you'll fight in.
Goddamned Bats: Mutation Agents. Looking like a weird cross between a rock, a tumor and a world war two sea mine, they show up in mid-stage horde areas and puff out a marginally damaging black gas around themselves regularly. Then they start upgrading nearby enemies into Elites. These would easily rank as Demonic Spiders if it weren't for the fact that they upgrade enemies at a fairly slow rate.
- Any enemy that locks down a hero is also a Goddamn Bat due to the afflicted hero requiring an ally to come and help them break free, Left 4 Dead style. If your co-op partners are a bit slow on the uptake this can go sour very very quickly, given regular enemies won't stop beating on you while you're locked down. This also means going off on your own in a co-op mission isn't such a good idea. Thankfully, these enemies don't show up during solo play.
- Anything with Persistence, signified by a glowing yellow halo above their heads, will get straight back up if killed. Fortunately, they are generally only able to do this once. Things with a Persistence Aura on the other hand, are out and out Demonic Spiders.
They Wasted a Perfectly Good Plot: An action based Spore game that will prove to be better than Galactic Adventures? Sounds awesome! Now, where do I build my monster? Wait, I can't make one from scratch? I can only use the preset ones? FFFFFFFFFFFFFFFUUUUUUUUUUUUUUU...
- The thing is, Maxis never claimed that Darkspore would be a "better version" of Spore. Right from its announcement, it was marketed as a completely different game. All the hype you mentioned was inflated by the fans.