I'll suggest 2 older titles that are still a lot of time and ones that I have spent a lot of time on, especially this first one:
Lode Runner 2. The goal is simple; collect the gold in the level, avoid being killed and get to the exit. At first it's easy, but later levels become increasingly hard. On top of that, there's a timer and scores to beat and when you beat those scores, why not challenge yourself and see if you can do even better? It's really a lot of fun when you figure it out. I have a review handy here: http://www.escapistmagazine.com/forums/read/326.258922-A-look-at-the-past-Lode-Runner-2 if you're more interested.
My other game is Moho, about imprisoned criminal robots in the future, figthing for a chance to be set free. Sounds bizarre, but the many different game modes and levels are quite fun and again, there are timers in the different levels, adding a lot to the reload value. Another review, if that interest you: http://www.escapistmagazine.com/forums/read/326.259075-A-look-at-the-past-Moho
EDIT: Oh, I just thought of another game. Robin Hood: Legend of Sherwood. A great and very fun game. It's a lot like Commandos and Desperados, the gameplay is very much the same as in those two games with controlling characters, avoid the guards/knocking them out, sneaking your way into a place, most of the time a castle and do perform some objective like rescuing a hostage or stealing money or something else. It's not exactly new, but it's not ugly to look at, in part because of the beautiful handdrawn backgrounds. I don't have any review for that, but I would definitely recommend it.
