Having not grown up in Toronto, I was only introduced to Playdium in my early 20s and all I can say is that I would have loved it as a spot to frequent whilst at high school!
3 stars because it's slightly over priced, but the choice of games at your disposal is impressive! Some of my favourites growing up like the Jurassic Park game, Sniper, Time Crisis are all available here but to be fair they don't have anything that's very unique to boast about here. And everything does seem dated here and new games would be very welcome.
The presence of a batting cage and go karting really does boost this place up although I've yet to try either. And the mini gold and "bungee trampoline" all add some "oomph" in to this 'dium.
If you're looking for nothing but a good time with arcadge games and you're in the area, this place is indeed the ideal spot for you to be at. You would have to put up with some younger kids and the odd annoying teenager, but that's to be expected.
You're given a preloaded card for the games and you're probably going to end up spending over $20/visit, add that to the fact that you don't get good food options this place just lands on the average side of a complete experience but for an afternoon of gaming you probably can't beat Playdium.