A nice casual match-three-or-more game mixed with a minor dose of RPG elements.
The versus mode against friends is nice, but the instructions with regards to port forwarding and sharing your IP address to be able to play against others is disappointing. Having a lobby and a friends list to find opponents would've been far more enjoyable.

Orcs Must Die 1 was already a thrilling game full of orc massacres and bloody trapalicious combo trickery, and now you can plot against the orcs with a friend!
It's a shame we lost the Weavers (I kinda liked that idea!), but the Trinkets make up for quite a bit. They prove far more useful and perhaps even needed than you might think at first.

I do think this game is far more FPS-oriented than OMD1 which felt more strategy/trap-oriented.

The story mode felt far too easy unfortunately and I breezed through it in one or two days, with only the last level being quite a challenge at first (till I discovered the magical combination of barricades, ice vents and archers!).
However, the Endless levels are horribly hard, and massively fun in Co-Op!

Buying upgrades still goes through skulls you've earned by finished levels, however there is no limit to them this time, with bonus skulls scattered throughout the levels, and extra skulls being earned in Endless mode for every x waves you finish.

First impressions after playing for a few hours:
Dodgy registration process: forcing username and password to lowercase (without informing the user of it!) and sending the user's password to their e-mail (sort of a security fail). Website interface partially french ("Ce nom d'utilidateur est disponible !"?) and requiring an annoying captcha verification.

Tutorials: nice enough and not too long. However, the Trade tutorial couldn't be completed (trades were impossible due to not enough units and money) and yet the tutorial said everything went successful.

Gameplay itself: controls work well, though the different zoning modes take a little getting used to. My first city failed to become profitable, but that's nothing new with sim games. :P
Looking forward to continuing, and perhaps start on a bit smaller scale this time.