No summary of the Gospel is going to be perfect and every summary is going to miss something. The bridge illustration, which shows how Jesus bridges the gap between sinful man and a holy God, captures well the aspect of Jesus being Savior. However, it doesn’t do a very good job of showing how someone needs to trust Christ as Lord and Ruler of their life as well. You can’t believe in Christ as Savior to forgive your sins but not have him also as Lord of your life who must be obeying in faithful devotion. The Bible has no category for someone who “accepts” Jesus as Savior but shows no interest in submitting their life to him.
A really great Gospel summary that corrects this imbalance is the Two Ways to Live summary. It should be coming out as a published little booklet in Thai in the very near future but I have a translation of it that I have been using and find it to be really helpful in helping people understand not only our separation from God because of sin, but also the need to be reconciled to Him as Lord and Ruler of our life. I include below two PDFs of the Thai version of Two Ways to Live that I have been using, which may be copied for personal and small group use. The original English version and other languages are available from Matthias Media.
The video below is an example of how Two Ways to Live can be presented as part of open air evangelism in Thailand. It has been put together by the Central Thailand Student Ministry team (part of Thai Christian Students/IFES) as part of their training program.