The Acer K520 has a maximum resolution of XGA (1024x768). That's 62% less resolution than the most common native projector resolution of 1080p (1920x1080).
An XGA (1024x768) native projector resolution is in fact the worst resolution across all similar spec projectors that were released around the same time as the K520.
The best resolution across similar types of multimedia projector is 1080p (1920x1080).
If the resolution of this multimedia projector is not high enough for you then you might also want to consider the Sony VPL-SW536C (WXGA (1280x800)), the Optoma HD30 (1080p (1920x1080)), or the LG PF80 (1080p (1920x1080)) which also has a higher rating.