The first movie was screened cinemas in Singapore in 2008 (but AFAIK was never put out on DVD ), while the 2nd movie (apparently) did not get a cinema release. However, I found out that http://www.gv.com.sg will be having a special (one-off) screening of "Mystery of the Abyss" on May 7
http://www.gv.com.sg/GVPromotionDetails#/promotion/94b03d3c-bb3e-424e-86ad-7965a7ba47d9