The Hugo Gernsback crashed ten years before the events of this game but the crew drop heat sinks when they die. Disposable heat sinks were only integrated in weapons of organics after the geth attacked the Citadel.
On various locations, various characters met in Mass Effect 1 state that they've been doing lots of things in the past few years (most notably Liara built up her empire in that time). Since there are only 2 years apart events of ME1 and ME2, those statements ofter are quite out of place.
In the codex entry of the Mass Relay the still image of the relay has a "LOADING" watermark in the lower left hand corner of the codex's image, even though nothing is loading when reading this entry which means the image is a direct screen shot grab from the first game.