Downhill Jam was the name of the Pheonix level in THPS1, arguably the worst Tony Hawk level ever.
The Hawk series has sucked for a while now and the last 2 titles have felt very rushed.
IMO, THPS1 was one of the best games ever made. THPS2 and THPS3 were just more of that awsomeness. THPS4 was crap compared to the first 3. It had crappy level design and the single player mission had you doing crap like riding in shopping carts.
THUG1 was actually a decent game. Not as Good as THPS1-3, but 10x better than THPS4. It had good level design and the transfers ability was great.
THUG2 was one of the worst games I've ever played. The worst level design out of any of the games in the series (and the new player models were terrible). This is a disgrace to the series.
THAW was also kinda crappy. All the extra moves they added over the years just made the game feel very bloated. The level design was only average.
What I want from a Tony Hawk game is THPS3 + transfers. That's it. Just keep that formula, add better visuals and more levels and I will keep buying the game for years. All the new tricks they add suck. I don't want to have to run up walls and do backflips. I want a skaing game, not a parkour game.
What makes a good Tony Hawk game is good skating, not that other crap they add. Keep the game simple and fun. This is 80% level design. If you have good levels with good lines then you will have a good game. They haven't concentrated on the levels since THPS3.