gixgox: As I wrote, I never downloaded anything from that site, so I don't have any experience with Toomky.
I have downloaded and installed Island Of Death from ToomkyGames.
When you click on a game and then on the green "Download for PC" bar a line with the following statement appears:
"You may be additionally asked to install other software products that may be interesting to you."
Installation worked fine and it didn't install a toolbar or other crap. After the installation is finished you can choose to start the game or install something called "ToomkyGames-Gadget" (see attached pic).
So if you're careful and make sure not to check that box it should be ok to download games from that site.
EDIT:
I just tried it and the game does try to connect to the internet when you're online. So either block the connection or play when you're offline.