Easy/hard aside, I think an exchange in the linked thread sums it up:
The game is great, mind you, but I daresay the timing element doesn’t contribute to enjoyment (IMHO), but rather to frustration.
Has anyone mentioned Bloxorz in this thread? It made the rounds of the Board a little while ago, probably ended a few marriages (through abandonment), and can be extraordinarily frustrating in a (IMHO) good way. Play at your own risk~
Ok, a little while back, I used to play a flash game that I cannot find anymore. The board was set up like a grid, and there were green drops of slime or whatever in some of the spots. The object was to add slime to a drop until it exploded, which sent slime to other spots. It took four drops to explode. You would get a limited number of drops, so you had to plan for chain reactions.
I think it was called Splat, but I can’t find it under that name. Anyone know what I’m talking about?
Here’s a pleasant little puzzle game I enjoyed greatly: http://www.leversgame.com/
Holy crap! Thank you so much!
Or maybe not. I’m gonna get fired :).
Excellent game. That one had me hooked (heh) when I first saw it.
OK, now you’ve done it!
Flash Circle TD
Flash Element TD
Onslaught
Vector TD
If you’d prefer something medieval,
BowMaster Prelude
CMC +fnord!
You use the little “power-ups” in the bottom left corner. Place them on the board, then hit go to have them change the ball’s direction, or move it, or whatever. There’s ramps, fans, batteries, fire, springs, etc…
Great game, just hit 44 
N has won awards for its simplicity and ingenius physics engine. My friends at work and I are addicted to it, and you can even edit levels, so we create levels for each other to beat. 
There was a good game a few holidays back. You wad Santa in a catapult, but you had to be careful not to overdo it or go over the cliff:
(mouse button to start, hold down to keep pulling back - let go to , well , let go)
Brian
final fantasy tacticish game - tactics 100. not as pretty as tactics arena, but it offers a fair fight as opposed to paying $ for better units.
…
Nanaca CRASH! is a fairly eccentric game, but it makes for a fun five minutes. It’s pretty easy to figure out, but since I remember it being in Japanese I’ll summarize: Essentially, you use your flying bicycle and extremely violent schoolmates to kick the nine hells out of some poor guy, sending him flying through the air. Each bounce takes away some of his momentum, which you can restore by hitting him again by clicking the left mouse.
And that’s pretty much it. If you hit him as he’s descending you’ll give him a horizontal boost, and if you hit him as he’s ascending you’ll bounce him against the pavement, giving a horizontal and vertical boost.