Usually, speedruns aren't actually faster than the TAS, unless the speedrun used some new technique was developed after the TAS was made. Normally the biggest different is that TASes and regular speedruns use different methods of timing.

TASes are pretty much always measured from power on to last button input required to trigger the credits. With normal speedrun, timing various from game to game, but a common method is timing from selecting new game to the last hit on the final boss. So games with long openings or with interactive post-final boss sequences that have to be played before the credits start would have inflated times on the TAS.

The TAS counts about an extra 15 seconds before the game starts. The TAS reaches the point the speed run stops counting at 18:52, and continues to play out the ending. So the TAS would be measured as about 18:37 using speed run timing, so the speed run is still genuinely faster than the TAS, but less than the official numbers indicate.

It seems like the speed run uses a glitch that the TAS deliberately avoided. From the TAS description:

> At the same time, a major new glitch allowing Ecco to go through nearly any wall was not used because the frequency of its use would make the run very repetitive.